The confrontation between the president and the prime minister, whose party dominates parliament, reached a critical point Monday after Yushchenko signed a decree to dissolve parliament and call early elections May 27.
"Sources in the presidential secretariat have said that Yushchenko is already preparing another anti-constitutional decree," Volodymyr Sivkovych of the Party of Regions said. "The Ukrainian president intends to dismiss the Cabinet of Yanukovych and take over executive powers."
"The decree would indicate that the president intends to usurp power and establish presidential dictatorship in the country," Sivkovych said, adding that no fair or democratic elections could therefore be expected.
The former Soviet nation of 47 million became mired in the current political deadlock after 11 members of opposition parties - the pro-presidential Our Ukraine and the Yulia Tymoshenko Bloc - defected to the ruling coalition in parliament.
Yushchenko, whose powers were drastically curtailed by a Cabinet law passed early this year, said the defections were against the Constitution. The prime minister reiterated his promise to revise the law on the Cabinet and to meet power-sharing commitments with the president if he backtracked on the decree to dissolve legislature.
The Supreme Rada continued work in defiance of the presidential decree, which it referred to the Constitutional Court Tuesday.
Yanukovych said Wednesday the Constitutional Court chairman, Ivan Dombrovskiy appointed in August on the presidential quota, could hand in his resignation, but that the court's press service has not confirmed the information.
The opposition bloc of Yulia Tymoshenko called on the president later Wednesday to protect Dombrovskiy against "the impudent, rude and illegal pressure" from the premier and the parliamentary speaker, calling it "political terror."
A total of 255 members of the Supreme Rada have gathered for an emergency session.
"We must be ready at all times to react to the illegal actions we have recently witnessed," said parliamentary Speaker Oleksandr Moroz.